<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        /**
         * 伪类== 状态
         * a link  visited hover active
         *   hover
        */
        a:link {
            color: #FF0000;
            text-decoration: none;
        }

        /* 未被访问的链接 */
        a:visited {
            color: #00FF00;
            text-decoration: underline;
        }

        /* 已被访问的链接 */
        a:hover {
            color: #FF00FF;
            text-decoration: underline;
        }

        /* 鼠标指针移动到链接上 */
        a:active {
            color: #0000FF;
            text-decoration: underline;
        }

        .btn{
            width: 100px;
            background-color: aliceblue;
        }

        /*情景色*/
        .success{
            background-color: #00FF00;
        }

        .success:hover{
            background-color: #1966ff;
        }

        .danger{
            background-color: #FF0000;
        }

        .danger:hover{
            background-color: #ff8592;
        }


        .box{
            width: 200px;
            height: 200px;
            background-color: greenyellow;
        }

        .box:hover{
            width: 100px;
            height: 100px;
            background-color: greenyellow;
        }

    </style>
</head>
<body>
<a href="1.hello.html">跳转</a>


<button class="btn success">
    提交
</button>
<button class="btn danger">
    提交2
</button>

<div class="box">

</div>
</body>
</html>